4 research outputs found
Accelerate & Actualize: Can 2D Materials Bridge the Gap Between Neuromorphic Hardware and the Human Brain?
Two-dimensional (2D) materials present an exciting opportunity for devices
and systems beyond the von Neumann computing architecture paradigm due to their
diversity of electronic structure, physical properties, and atomically-thin,
van der Waals structures that enable ease of integration with conventional
electronic materials and silicon-based hardware. All major classes of
non-volatile memory (NVM) devices have been demonstrated using 2D materials,
including their operation as synaptic devices for applications in neuromorphic
computing hardware. Their atomically-thin structure, superior physical
properties, i.e., mechanical strength, electrical and thermal conductivity, as
well as gate-tunable electronic properties provide performance advantages and
novel functionality in NVM devices and systems. However, device performance and
variability as compared to incumbent materials and technology remain major
concerns for real applications. Ultimately, the progress of 2D materials as a
novel class of electronic materials and specifically their application in the
area of neuromorphic electronics will depend on their scalable synthesis in
thin-film form with desired crystal quality, defect density, and phase purity.Comment: Neuromorphic Computing, 2D Materials, Heterostructures, Emerging
Memory Devices, Resistive, Phase-Change, Ferroelectric, Ferromagnetic,
Crossbar Array, Machine Learning, Deep Learning, Spiking Neural Network
Analog Content-Addressable Memory from Complementary FeFETs
To address the increasing computational demands of artificial intelligence
(AI) and big data, compute-in-memory (CIM) integrates memory and processing
units into the same physical location, reducing the time and energy overhead of
the system. Despite advancements in non-volatile memory (NVM) for matrix
multiplication, other critical data-intensive operations, like parallel search,
have been overlooked. Current parallel search architectures, namely
content-addressable memory (CAM), often use binary, which restricts density and
functionality. We present an analog CAM (ACAM) cell, built on two complementary
ferroelectric field-effect transistors (FeFETs), that performs parallel search
in the analog domain with over 40 distinct match windows. We then deploy it to
calculate similarity between vectors, a building block in the following two
machine learning problems. ACAM outperforms ternary CAM (TCAM) when applied to
similarity search for few-shot learning on the Omniglot dataset, yielding
projected simulation results with improved inference accuracy by 5%, 3x denser
memory architecture, and more than 100x faster speed compared to central
processing unit (CPU) and graphics processing unit (GPU) per similarity search
on scaled CMOS nodes. We also demonstrate 1-step inference on a kernel
regression model by combining non-linear kernel computation and matrix
multiplication in ACAM, with simulation estimates indicating 1,000x faster
inference than CPU and GPU
Tuning Polarity in WSe<sub>2</sub>/AlScN FeFETs via Contact Engineering
Recent
advancements in ferroelectric field-effect transistors
(FeFETs)
using two-dimensional (2D) semiconductor channels and ferroelectric
Al0.68Sc0.32N (AlScN) allow high-performance
nonvolatile devices with exceptional ON-state currents, large ON/OFF
current ratios, and large memory windows (MW). However, previous studies
have solely focused on n-type FeFETs, leaving a crucial gap in the
development of p-type and ambipolar FeFETs, which are essential for
expanding their applicability to a wide range of circuit-level applications.
Here, we present a comprehensive demonstration of n-type, p-type,
and ambipolar FeFETs on an array scale using AlScN and multilayer/monolayer
WSe2. The dominant injected carrier type is modulated through
contact engineering at the metal–semiconductor junction, resulting
in the realization of all three types of FeFETs. The effect of contact
engineering on the carrier injection is further investigated through
technology-computer-aided design simulations. Moreover, our 2D WSe2/AlScN FeFETs achieve high electron and hole current densities
of ∼20 and ∼10 μA/μm, respectively, with
a high ON/OFF ratio surpassing ∼107 and a large
MW of >6 V (0.14 V/nm)